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Robertson: Prepare, explosive eruptions could continue for a year


Robertson: Prepare, explosive eruptions could continue for a year
Professor Richard Robertson. (GP)

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Director of the University of the West Indies Seismic Research Centre Professor Richard Robertson told Babadians on Monday that they may have to deal with ash from St Vincent’s La Soufriere Volcano for up to a year.

Roberston joined Minister of Home Affairs Wilfred Abrahams during a live emergency update on the La Soufriere Volcano on Monday.

He said that while the possibility that explosive eruptions could continue for a year was not news Barbadians wanted, they could implement measures to mitigate the effects of the ash.

Robertson said the energy observed during the current explosive eruptions of La Soufriere is similar to the 1902 eruptions. Hence, the time span of this explosive state is unclear and can vary from weeks to a year, given past experience.

The Vincentian volcanologist said there may or may not be ash fall, but it seems as though the episodic behavior will continue.

He told Barbadians: As long as La Soufriere is erupting explosively, Barbadians will have ash fall.

“Hopefully for your sake, for all our sakes, this volcano goes back to sleep as quickly as possible but there is no indication currently that it is heading in that direction.

“Fortunately for us in the region, our volcanoes don’t erupt very often, but when they do, we just have to allow them to do what they are doing and take measures . . . . ”

Robertson said the situation is still evolving but at the moment the amount of energy looks like 1902.

“That’s why I said it could go on as long as a year.

“In 1902, there were months when nothing happened. We hope that we are wrong but you have to prepare. . .”

Robertson explained that explosive eruptions of volcanoes means that from time to time there are explosions from the summit of the volcano, resulting in rocks exploding and breaking up into small pieces. The rocks are then thrown into the air at high altitudes and, once they get to  a certain height, they can be taken in any direction – hence the effect of ash in Barbados.

He said episodic explosions were described as episodes in which explosive activity or venting of ash occurs, interspersed by periods of relative quiet. That pattern has been sustained since the explosive eruptions began on Friday. Robertson made the point that eruptions had moved from an effusive state to an explosive state. Effusive eruptions began in December 2020.

What varies with these current explosive eruptions, he said, is the intensity of the explosion. The more intense explosive eruptions are what causes the ash plumes to travel to Barbados.

Apart from Monday morning, he said “columns during the day have tended to be not very high in the atmosphere” and the one on Monday afternoon was mostly steam. The earlier eruption occurred around 4:15 a.m. (KG)